Environmental sounds are typically comprised of a mixture of various sound wave frequencies. Exposure to sound waves of some frequencies under conditions of severe impact can damage the auditory organ and cause hearing problems, including deafness. Injurious noises such as those caused by explosions or bursts are often comprised of a mixture of sound wave frequencies. These disturbing frequencies are in both the high and low frequency bands. Individuals who are frequently exposed to such disturbing and sometimes dangerous frequencies run the risk of incurring such injury. These individuals include demolition workers and operators of heavy, noisy equipment such as firearms to name only a few.
Sound attenutation devices are known which specifically address this problem. These include conventional earmuffs, earplugs and the like which function to reduce the negative effects of exposure to dangerous frequencies by limiting the entry of all sound waves into the auditory organ. These previous devices, however, suffer from the disadvantage that auditory access to environmental sounds of relatively risk free frequencies is also limited. Use of such previous devices, although protective to some extent against the effects of exposure to dangerous frequencies, creates a new danger of shutting out all environmental sounds including those of speech.
Other devices which are typically comprised of a plurality of sound absorbing plates are known which are capable of filtering out noises of certain sound wave frequencies while leaving others undisturbed. These prior art devices, however selective, cannot simultaneously attenuate sound waves of both high and low frequencies. Rather, they are selective of a limited frequency band. The disadvantage of these devices are obvious inasmuch as many injurious noises are comprised of multiple frequencies.
It is therefore an object of the present invention to provide a device heretofore unkown which is capable of attentuating sound waves of both high and low frequencies bands.